30 results on '"Elena Un"'
Search Results
2. Impaired Spirometry and COPD Increase the Risk of Cardiovascular Disease
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Suurya Krishnan, Wan C. Tan, Raquel Farias, Shawn D. Aaron, Andrea Benedetti, Kenneth R. Chapman, Paul Hernandez, François Maltais, Darcy D. Marciniuk, Denis E. O’Donnell, Don D. Sin, Brandie Walker, Jean Bourbeau, J. Mark FitzGerald, Shawn Aaron, Dany Doiron, Palmina Mancino, Pei Zhi Li, Dennis Jensen, Carolyn Baglole, Yvan Fortier, Don Sin, Julia Yang, Jeremy Road, Joe Comeau, Adrian Png, Kyle Johnson, Harvey Coxson, Jonathon Leipsic, Cameron Hague, Miranda Kirby, Zhi Song, Christine Lo, Sarah Cheng, Elena Un, Cynthia Fung, Wen Tiang Wang, Liyun Zheng, Faize Faroon, Olga Radivojevic, Sally Chung, Carl Zou, Jacinthe Baril, Laura Labonte, Kenneth Chapman, Patricia McClean, Nadeen Audisho, Curtis Dumonceaux, Lisette Machado, Scott Fulton, Kristen Osterling, Denise Wigerius, Kathy Vandemheen, Gay Pratt, Amanda Bergeron, Denis O’Donnell, Matthew McNeil, Kate Whelan, Cynthia Brouillard, Darcy Marciniuk, Ron Clemens, Janet Baran, and Candace Leuschen
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Pulmonary and Respiratory Medicine ,Cardiology and Cardiovascular Medicine ,Critical Care and Intensive Care Medicine - Published
- 2023
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3. Literacy as a Social Practice: Exploring Teacher Representations
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Elena UNGUREANU
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literacy ,social practice ,james paul gee ,primary education ,pedagogic practices ,qualitative research ,Education (General) ,L7-991 ,Theory and practice of education ,LB5-3640 - Abstract
This study explores how literacy is conceptualized by teachers in two primary classrooms, drawing upon James Paul Gee's theoretical framework on literacy as a social practice. The research is guided by two questions: How do teachers conceptualize literacy within the context of their classrooms? How do contextual characteristics position students’ identities as literacy learners/users? Through thematic analysis of semi-structured interviews, three predominant themes were developed: a narrow focus of literacy, deficit-oriented framing of student abilities, and teacher-centered pedagogy. The findings reveal that teachers often emphasize foundational writing skills and view literacy through a lens of deficiency, which shapes students' identities as passive learners. This research underscores the need for inclusive and equitable literacy education that acknowledges diverse backgrounds and experiences, advocating for pedagogical shifts that empower students as active participants in their literacy development.
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- 2024
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4. Constructing Ability in the Classroom: A Descriptive Analysis of Pedagogical Practices in Primary Education
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Elena UNGUREANU
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ability ,bernstein ,social constructionism ,primary education ,pedagogic practices ,Education (General) ,L7-991 ,Theory and practice of education ,LB5-3640 - Abstract
In this article I explore how certain pedagogic practices construct students’ ability as visible. The concept of ability is viewed as constructed, put into place by specific educational practices, rather than a fixed traitof the students. Conducted in two primary classrooms, this study employs observational methods complemented by audio-video recording. Through the analysis of the recordings and transcripts, I identify and thematize several pedagogical practices, used to organize learning activities. The analysis is framed by Basil Bernstein's concepts of visible pedagogy and framing, complemented by Rosenholtz and Simpson’s (1984) view of ability as a socially constructed phenomenon. The findings are organized around two main themes that align with Bernstein’s concepts of visible pedagogy: (1) Practices that make visible the means for ability development, and (2) Practices that make visible the rhythm of ability. The study aims to contribute to our understanding of how ability, a central concept in education, can be viewd as socially constructed by pedagogical practices, understood as an alternative to the developmentalist view that sees the same concept as fix, normally disperesed and liniearly developed.
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- 2024
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5. In Situ and Partial In Situ Synthesis of Cellulose Magnetite/Maghemite Composites
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Razvan Rotaru, Maria Emiliana Fortună, Elena Ungureanu, Ovidiu Ungureanu, Andrei Dascalu, and Valeria Harabagiu
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cellulose ,composites ,maghemite ,magnetite ,magnetic properties ,ultrasonication ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The current study aims to prepare ferromagnetic iron oxides (magnetite and/or maghemite) using the coprecipitation method of an iron salt in a basic environment stimulated by ultrasound, with cellulose added at the start of the synthesis and after 15 min in order to perform an in situ and partial in situ synthesis. The structures, morphology, and properties of composites are analyzed by IR, XRD, SEM, TEM, TGA, DSC, and magnetic measurements. The cumulative effect of the ultrasonic waves is observed by a reduction in the degree of crystallinity of the native cellulose compared to the composites (from 73.2 to 36.4, respectively 38.3). The vibrating sample magnetic measurement shows a single hysteresis curve characteristic of ferromagnetic materials with superparamagnetic properties.
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- 2025
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6. Advances in Cellulose-Based Hydrogels: Current Trends and Challenges
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Bogdan-Marian Tofanica, Aleksandra Mikhailidi, Costel Samuil, Ovidiu C. Ungureanu, Maria E. Fortună, and Elena Ungureanu
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cellulose ,cellulose-based gels ,hydrogels ,gels ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
This paper provides a solid foundation for understanding the synthesis, properties, and applications of cellulose-based gels. It effectively showcases the potential of these gels in diverse applications, particularly in biomedicine, and highlights key synthesis methods and properties. However, to push the field forward, future research should address the gaps in understanding the environmental impact, mechanical stability, and scalability of cellulose-based gels, while also considering how to overcome barriers to their industrial use. This will ultimately allow for the realization of cellulose-based gels in large-scale, sustainable applications.
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- 2024
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7. Evaluation of the In Vitro Behavior of Electrochemically Deposited Plate-like Crystal Hydroxyapatite Coatings
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Cosmin M. Cotrut, Alexandru Blidisel, Diana M. Vranceanu, Alina Vladescu (Dragomir), Elena Ungureanu, Iulian Pana, Mihaela Dinu, Catalin Vitelaru, Anca C. Parau, Vasile Pruna, Mihai S. Magurean, and Irina Titorencu
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biomimetic ,surface modification ,hydroxyapatite coatings ,electrochemical deposition ,biocompatibility ,Technology - Abstract
The purpose of coatings is to protect or enhance the functionality of the substrate material, irrespective of the field in which the material was designed. The use of coatings in medicine is rapidly expanding with the objective of enhancing the osseointegration ability of metallic materials such as titanium. The aim of this study was to obtain biomimetic hydroxyapatite (HAp)-based coatings on titanium by using the pulsed galvanostatic method. The morphology of the HAp-based coatings revealed the presence of very thin and wide plate-like crystals, grown perpendicular to the Ti substrate, while the chemical composition highlighted a Ca/P ratio of 1.66, which is close to that of stoichiometric HAp (1.67). The main phases and chemical bonds identified confirmed the presence of the HAp phase in the developed coatings. A roughness of 228 nm and a contact angle of approx. 17° were obtained for the HAp coatings, highlighting a hydrophilic character. In terms of biomineralization and electrochemical behavior, it was shown that the HAp coatings have significantly enhanced the titanium properties. Finally, the in vitro cell tests carried out with human mesenchymal stem cells showed that the Ti samples coated with HAp have increased cell viability, extracellular matrix, and Ca intracellular deposition when compared with the uncoated Ti, indicating the beneficial effect.
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- 2024
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8. CORNHUSK POWDERS AS ADSORBENTS FOR NITRITES IN SOLUTION: A THERMODYNAMIC AND KINETIC APPROACH
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Alina Elena TROFIN, Elena UNGUREANU, Iuliana MOTRESCU, Lucia Carmen TRINCĂ, Denis Constantin ȚOPA, and Diana Beatrice EPERJESSY
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cornhusks powder ,nitrite removal ,waste valorisation ,Environmental sciences ,GE1-350 ,Agriculture - Abstract
The retention of nitrite ions in solutions of different concentrations by three cornhusks-based powders was analyzed. Natural cornhusk powder (NCHP), as waste obtained from local market, the alkalized cornhusk powder (ACHP) and the biochar from the original material (CHBC) have been characterized through scanning electron microscopy (SEM) and elemental composition EDAX – TEAM analysis (Energy dispersive analysis X-ray – Texture and ele-mental analytical microscopy) and tested for the removal of nitrite ions. The influence of initial nitrite concentration and contact time was studied under slow stirring rate conditions (150 rpm). For all three adsorbents both Freundlich and Langmuir isotherm equations described the process with R2 > 0.95, denoting physical adsorption and chemisorption on the surface. The estimated retained quantities (mg·g-1) determined from isotherms were 4.4783 (NCHP), 8.3542 (ACHP) and 8.7413 (CHBC). The Ho&McKay model was better adjusted to the adsorption data with R2 > 0.985, while the Lagergren model produced regression factors between 0.61 and 0.88. Considering the biggest concentration of nitrite solution of 50 mg·L-1 and the longest contact time of 150 minutes, the equilibrium capacity qe (mg·g-1) predicted by the Ho&McKay model for the considered adsorbents were: 4.5065 (NCHP), 8.5179 (ACHP) and 8.9445 (CHBC) compared to the obtained qt (mg·g-1) of 4.4384 (NCHP), 8.0685 (ACHP) and 8.5753 (CHBC). The nitrite uptake in the experiments reached a maximum of 2.2192 mg·g-1 on NCHP, 4.0342 mg·g-1 on ACHP and 4.2877 mg·g-1 on CHBC. Considering the cost-effective treatment steps, there is the possibility of valorising an important amount of waste as adsorbent materials.
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- 2023
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9. Clinical appropriateness of the use of early warning scores in medical wards
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Saleem Chaudhri, Rahul Mukherjee, Ambreen Sadiq, Samuel Strain, Monisha Premchand, Aneeka Shah, Christopher Peet, Elena Un, and Clara E. Green
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Identification (information) ,Warning system ,Early Warning Score ,business.industry ,MEDLINE ,Humans ,Medicine ,General Medicine ,Medical emergency ,Quality Improvement and Patient Safety ,business ,medicine.disease ,Hospitals - Abstract
Early warning scores (EWS) are vital tools in the identification of clinically deteriorating patients. They use a combination of physiological parameters to create an aggregate score, alerting medical teams to the acute deterioration of patients. This score impacts on the frequency of patient
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- 2020
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10. Master’s Portrait: Eugeniu Coșeriu
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Elena UNGUREANU
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eugeniu coșeriu ,integral linguistics ,romanian language ,the coșeriu centenary ,coșeriu’s testament ,the integral coșeriu ,Literature (General) ,PN1-6790 - Abstract
Coșeriu approached the field of linguistics from a perspective of universality, something that few linguists could achieve in their lifetime. The perspective is due to the freedom of thought of the renowned linguist of Bessarabian origin, Coșeriu’s knowledge of classical languages, his global vision of language and its location at the center of human disciplines. With a good school at home (he is a graduate of the famous high school for boys “Ion Creangă” from Bălți), these qualities of the distinguished man of letters were cemented and asserted in Italy, Uruguay or Germany, places abroad where he practiced and deepened important research, which has not lost its relevance; on the contrary, whose value increases with the years. Coșeriu being rather a linguist of the future than of the present. The Cosherian concept of integral linguistics treats the discipline as a science of culture, placing speech before language, the former being much broader and more complex. Namely, the famous polemic with Saussure allowed Coșeriu to establish and substantiate the triad language – speech – norm, which he exemplarily illustrated with the help of European languages, but also with subtle analyzes of the Romanian language. The return to his homeland led him to actively support the fight of his compatriots for the triumph of scientific truth regarding the correct name of the language spoken by Moldovans: the Romanian language for the entire Carpatho-Danubian-Dniester space. The Coșeriu centenary brought to the attention of philologists the duty of studying the work in depth, translating it into popular languages, and last but not least, editing Coșeriu’s complete work.
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- 2023
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11. Polysilane–Barium Titanate Polymeric Composite Obtained through Ultrasonication
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Răzvan Rotaru, Maria Emiliana Fortună, Elena Ungureanu, and Liviu Sacarescu
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barium titanate (BT) ,composite ,polysilane (PSH) ,semiconductor ,ultrasonication ,Inorganic chemistry ,QD146-197 - Abstract
This work describes the synthesis of a polysilane (PSH)–barium titanate (BT) ferroelectric polymer composite that keeps stable in the presence of ultraviolet light (UV). To evaluate the stability in the presence of UV radiation and the mechanism of interaction between the PSH matrix and BT, FTIR measurements were carried out. The UV/VIS absorption measurement reveals that PSH absorbs strongly in the ultraviolet range, while the composite behaves similarly to BT. Although PSH is a semiconductor, the dielectric spectrometry analysis determined that BT is a ferroelectric material due to its high dielectric constant and low dielectric losses. In contrast to the polymer matrix, the composite polymer has a greater dielectric constant and a lower loss permittivity. PSH is a semiconductor, as indicated by its electrical conductivity of 10−5 S/cm; nevertheless, the UV-irradiated polymer has antistatic properties (10−8 S/cm). Irradiated or not, the polymer composite is a semiconductor, with conductivity of 10−6 S/cm, significantly lower than that of PSH. The interaction with electromagnetic radiation indicates electromagnetic shielding behavior for both BT (highest absorption magnitude of −57 dB) and the polymer composite (maximum absorption magnitudes range from 8.4 to −15.2 dB). Based on these research results, the novel composite with specific characteristics may be used in electronic applications in UV-irradiated conditions.
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- 2024
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12. Agriculture 4.0: Polymer Hydrogels as Delivery Agents of Active Ingredients
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Aleksandra Mikhailidi, Elena Ungureanu, Bogdan-Marian Tofanica, Ovidiu C. Ungureanu, Maria E. Fortună, Dan Belosinschi, and Irina Volf
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bio-based hydrogels ,delivery systems ,fertilizer ,pesticide ,plant development ,life cycle assessment ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
The evolution from conventional to modern agricultural practices, characterized by Agriculture 4.0 principles such as the application of innovative materials, smart water, and nutrition management, addresses the present-day challenges of food supply. In this context, polymer hydrogels have become a promising material for enhancing agricultural productivity due to their ability to retain and then release water, which can help alleviate the need for frequent irrigation in dryland environments. Furthermore, the controlled release of fertilizers by the hydrogels decreases chemical overdosing risks and the environmental impact associated with the use of agrochemicals. The potential of polymer hydrogels in sustainable agriculture and farming and their impact on soil quality is revealed by their ability to deliver nutritional and protective active ingredients. Thus, the impact of hydrogels on plant growth, development, and yield was discussed. The question of which hydrogels are more suitable for agriculture—natural or synthetic—is debatable, as both have their merits and drawbacks. An analysis of polymer hydrogel life cycles in terms of their initial material has shown the advantage of bio-based hydrogels, such as cellulose, lignin, starch, alginate, chitosan, and their derivatives and hybrids, aligning with sustainable practices and reducing dependence on non-renewable resources.
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- 2024
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13. A2 milk - Advantages and Challenges in the Manufacturing of Dairy Products
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Adina-Mirela Ariton, Andra-Sabina Neculai-Văleanu, Ioana Poroșnicu, and Elena Ungureanu
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bovine milk ,a2 milk vs a1 ,dairy products ,Agriculture ,Technology ,Science - Abstract
A2 milk is characterized by a difference in the amino acid at position 67 of the β-casein polypeptide chain, which releases much smaller amounts of bioactive opioid peptide β-casomorphin - 7 upon digestion. Milk consumption may lead to discomfort due to the presence of A1 beta-casein protein. A2 milk is the preferable alternative for people with mild lactose intolerance or lactose sensitivity because it does not include A1 protein, which is thought to be kinder to the digestive system. The need for healthy and minimally processed dairy products, the growing awareness of dairy-related sensitivities, as well as the growing interest in organic and natural food options are some of the major reasons driving the expansion of the A2 milk market. The purpose of this review is to present the advantages and challenges of using A2 milk in the manufacturing of dairy products.
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- 2024
14. In Vitro Characterization of Hydroxyapatite-Based Coatings Doped with Mg or Zn Electrochemically Deposited on Nanostructured Titanium
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Diana M. Vranceanu, Elena Ungureanu, Ionut C. Ionescu, Anca C. Parau, Vasile Pruna, Irina Titorencu, Mihaela Badea, Cristina-Ștefania Gălbău, Mihaela Idomir, Mihaela Dinu, Alina Vladescu (Dragomir), and Cosmin M. Cotrut
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coatings ,biofunctionalization ,doped hydroxyapatite ,electrochemical behavior ,biocompatibility ,antibacterial ,Technology - Abstract
Biomaterials are an important and integrated part of modern medicine, and their development and improvement are essential. The fundamental requirement of a biomaterial is found to be in its interaction with the surrounding environment, with which it must coexist. The aim of this study was to assess the biological characteristics of hydroxyapatite (HAp)-based coatings doped with Mg and Zn ions obtained by the pulsed galvanostatic electrochemical method on the surface of pure titanium (cp-Ti) functionalized with titanium dioxide nanotubes (NTs TiO2) obtained by anodic oxidation. The obtained results highlighted that the addition of Zn or Mg into the HAp structure enhances the in vitro response of the cp-Ti surface functionalized with NT TiO2. The contact angle and surface free energy showed that all the developed surfaces have a hydrophilic character in comparison with the cp-Ti surface. The HAp-based coatings doped with Zn registered superior values than the ones with Mg, in terms of biomineralization, electrochemical behavior, and cell interaction. Overall, it can be said that the addition of Mg or Zn can enhance the in vitro behavior of the HAp-based coatings in accordance with clinical requirements. Antibacterial tests showed that the proposed HAp-Mg coatings had no efficiency against Escherichia coli, while the HAp-Zn coatings registered the highest antibacterial efficiency.
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- 2024
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15. Adsorption of Ni(II) from Aqueous Media on Biodegradable Natural Polymers—Sarkanda Grass Lignin
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Elena Ungureanu, Costel Samuil, Denis C. Țopa, Ovidiu C. Ungureanu, Bogdan-Marian Tofanică, Maria E. Fortună, and Carmen O. Brezuleanu
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adsorption ,Ni(II) ions ,Sarkanda grass lignin ,pollution ,germination ,Crystallography ,QD901-999 - Abstract
Heavy metals are pollutants that pose a risk to living systems due to their high toxicity and ability to accumulate and contaminate. This study proposes an alternative approach to the static adsorption of Ni(II) from aqueous media using Sarkanda grass lignin crystals, the non-cellulosic aromatic component of biomass, as an adsorbent substrate. To determine the best experimental conditions, we conducted tests on several parameters, including the initial and adsorbent solution pH, the concentration of Ni(II) in the aqueous solution, the amount of adsorbent used, and the contact time at the interface. The lignin’s adsorption capacity was evaluated using the Freundlich and Langmuir models to establish equilibrium conditions. The Lagergren I and Ho–McKay II kinetic models were used to determine the adsorption mechanism based on surface analyses and biological parameters such as the number of germinated seeds, energy, and germination capacity in wheat caryopses (variety Glosa) incorporated in the contaminated lignin and in the filtrates resulting from phase separation. The results suggest that Sarkanda grass lignin is effective in adsorbing Ni(II) from aqueous media, particularly in terms of adsorbent/adsorbate dosage and interfacial contact time.
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- 2024
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16. Hybrid Siloxane Materials Based on a Mutually Reactive Epoxy–Amine System: Synthesis, Structure, and Thermal Stability Investigations
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Maria Emiliana Fortună, Maria Ignat, Niţă Tudorachi, Elena Ungureanu, Răzvan Rotaru, and Valeria Harabagiu
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p-phenylenediamine (PPD) ,1,1,3,3 tetramethyldisiloxane (DS) ,hybrid materials ,thermal stability ,Inorganic chemistry ,QD146-197 - Abstract
Hybrid siloxane materials based on a mutually reactive epoxy–amine system are organic-inorganic hybrid materials synthesized via the sol–gel reaction of siloxane precursors, followed by the polymerization of organo-functionalized oligosiloxanes. Therefore, using a new hybrid system as the reaction product resulting from the reaction between 1,3-bis(3-glycidoxypropyl)-l, 1,3,3-tetramethyldisiloxane—C16H34O5Si2—(gp-DS) and p-phenylenediamine—C6H4(NH2)2—(PPD), an aromatic diamine, was obtained. The chemical structure of the synthesized hybrid siloxane material was confirmed via Fourier Transform Infra-Red (FTIR) spectroscopy, mass spectrometry (MS), and 1H-NMR spectroscopy. The morphology and surface chemical composition was highlighted via scanning electron microscopy (SEM) equipped with an EDX elemental analysis system. Further, the thermal stabilities of the prepared hybrid siloxane and its precursors have been investigated via thermogravimetric analysis (TGA), proving the modification of epoxy-functional disiloxanes with a paraphenylenediamine reagent that made it possible to produce hybrid siloxane materials with very good thermal stabilities and dual weak hydrophilic/hydrophobic surfaces.
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- 2024
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17. POTENTIAL VALORISATION OF PROTOBIND 1000 AS ADSORBENT FOR Pb 2+ AND Zn 2+
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Alina Elena TROFIN, Elena UNGUREANU, Lucia Carmen TRINCĂ, Maria Emiliana FORTUNĂ, and Diana Beatrice EPERJESSY
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adsorption ,protobind 1000 (pb 1000) ,lead ,zinc ,Environmental sciences ,GE1-350 ,Agriculture - Abstract
The adsorption of metal ions from increasing concentrations in aqueous solutions by modified straw lignin Protobind 1000 was studied. The effect of metallic ion concentrations (from 20.72 to 207.2 mg·L-1 for Pb2+ and from 6.538 to 65.38 mg·L-1 for Zn2+) and contact time (30, 60 and 90 minutes) were studied at pH = 6 and 200C. Langmuir and Freundlich isotherm equations were applied to assess equilibrium data and the kinetics of the adsorption processes were analysed using Lagergren pseudo first order and Ho&McKay pseudo second order models. The results show that the adsorption processes reached equilibrium after 90 minutes, but similar values were registered after 60 minutes. The Freundlich isotherm described the process better, denoting chemisorption with the formation of ion-lignin complex structures. The Ho&McKay model fit the adsorption data better with regression coefficients equal to 1 compared to the Lagergren model, where the regression factors varied between 0.72 and 0.95. For the maximum concentration of lead solution and the longest adsorption time of 90 minutes, the Ho&McKay model predicted an equilibrium capacity qe of 13.1406 mg·g-1 compared to the 13.1398 mg·g-1 obtained. For zinc adsorption, the same maximum concentration and time were considered, and the pseudo-second order model predicted a qe of 12.6743 mg·g-1 compared to the obtained value of 12.6714 mg·g-1. The uptake of lead was greater on 0.15 g of adsorbent (a maximum of 27.23 mg·g-1) than the zinc uptake (a maximum of 8.28 mg·g-1), for all analysed concentrations.
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- 2022
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18. Selection of motion management in liver stereotactic body radiotherapy and its impact on treatment time
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Nicholas Hardcastle, Mathieu Gaudreault, Adam U. Yeo, Elena Ungureanu, Cathy Markham, Rebecca Barnes, Sarat Chander, and Julie Chu
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Liver ,Stereotactic body radiation therapy ,Motion management ,exhale breath hold. Stereotactic ablative body radiotherapy ,Abdominal compression ,Medical physics. Medical radiology. Nuclear medicine ,R895-920 ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Background and purpose: Reduction of respiratory tumour motion is important in liver stereotactic body radiation therapy (SBRT) to reduce side effects and improve tumour control probability. We have assessed the distribution of use of voluntary exhale breath hold (EBH), abdominal compression (AC), free breathing gating (gating) and free breathing (FB), and the impact of these on treatment time. Materials and Methods: We assessed all patients treated in a single institution with liver SBRT between September 2017 and September 2021. Data from pre-simulation motion management assessment using fluoroscopic assessment of liver dome position in repeat breath holds, and motion with and without AC, was reviewed to determine liver dome position consistency in EBH and the impact of AC on motion. Treatment time was assessed for all fractions as time from first image acquisition to last treatment beam off. Results: Of 136 patients treated with 145 courses of liver SBRT, 68 % were treated in EBH, 20 % with AC, 7 % in gating and 5 % in FB. AC resulted in motion reduction
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- 2023
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19. Cellulose-Based Metallogels—Part 3: Multifunctional Materials
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Aleksandra Mikhailidi, Elena Ungureanu, Dan Belosinschi, Bogdan-Marian Tofanica, and Irina Volf
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metallogels ,hydrogels ,cellulose ,metal nanoparticles ,drug delivery ,tissue engineering ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
The incorporation of the metal phase into cellulose hydrogels, resulting in the formation of metallogels, greatly expands their application potential by introducing new functionalities and improving their performance in various fields. The unique antiviral, antibacterial, antifungal, and anticancer properties of metal and metal oxide nanoparticles (Ag, Au, Cu, CuxOy, ZnO, Al2O3, TiO2, etc.), coupled with the biocompatibility of cellulose, allow the development of composite hydrogels with multifunctional therapeutic potential. These materials can serve as efficient carriers for controlled drug delivery, targeting specific cells or pathogens, as well as for the design of artificial tissues or wound and burn dressings. Cellulose-based metallogels can be used in the food packaging industry to provide biodegradable and biocidal materials to extend the shelf life of the goods. Metal and bimetallic nanoparticles (Au, Cu, Ni, AuAg, and AuPt) can catalyze chemical reactions, enabling composite cellulose hydrogels to be used as efficient catalysts in organic synthesis. In addition, metal-loaded hydrogels (with ZnO, TiO2, Ag, and Fe3O4 nanoparticles) can exhibit enhanced adsorption capacities for pollutants, such as dyes, heavy metal ions, and pharmaceuticals, making them valuable materials for water purification and environmental remediation. Magnetic properties imparted to metallogels by iron oxides (Fe2O3 and Fe3O4) simplify the wastewater treatment process, making it more cost-effective and environmentally friendly. The conductivity of metallogels due to Ag, TiO2, ZnO, and Al2O3 is useful for the design of various sensors. The integration of metal nanoparticles also allows the development of responsive materials, where changes in metal properties can be exploited for stimuli-responsive applications, such as controlled release systems. Overall, the introduction of metal phases augments the functionality of cellulose hydrogels, expanding their versatility for diverse applications across a broad spectrum of industries not envisaged during the initial research stages.
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- 2023
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20. Bovine Colostrum Management and the Factors Influencing its Quality
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Adina-Mirela Ariton, Andra-Sabina Neculai-Văleanu, Ciprian Radu, Ioana Porosnicu, and Elena Ungureanu
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bovine colostrum ,igg concentration ,management ,quality ,Agriculture ,Technology ,Science - Abstract
The mammary gland's secretion, called colostrum, is synthesized throughout the last weeks of pregnancy and the first few days following calving. It is meant to give the calf the necessary nutrients and physiologically active substances. High immunoglobulin concentration and low pathogen load define high-quality colostrum. The amount and quality of colostrum that is available and the timing of the first feeding after birth both have an impact on the level of immunity. Heifers produce substantially less colostrum than cows do, and the breed has a big impact as well. Colostrum handling and storage techniques, as well as milking procedures are essential steps toward quality colostrum management on dairy farms. This review focuses on colostrum management, methods, and techniques for assessing colostrum quality and the factors that influence bovine colostrum quality.
- Published
- 2023
21. Distribution and species composition of zooplankton (rotifers and crustaceans) in the Basin of the Middle Volga River, Russia
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Oksana Mukhortova, Stepan Senator, and Elena Unkovskaya
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dataset ,occurrence ,zooplankton ,Rotifera ,Crusta ,Biology (General) ,QH301-705.5 - Abstract
The presented dataset contains information on the distribution and species composition of zooplankton (rotifers and crustaceans) registered in the Basin of the Middle Volga River, Russia. The studies have been performed in the Kuibyshev Reservoir (Samara Oblast and the Republic of Tatarstan), the Saratov Reservoir (Samara Oblast), in several lakes (Raifskoe, Gniloe, Krugloe and Lenevo) in the Volzhsko-Kamsky State Biosphere Reserve (Republic of Tatarstan) and in Lake Aslikul, one of the largest lakes of the Middle Volga River Basin, located in the Asly-Kul Natural Park (Republic of Bashkortostan). The hydrobiological data were obtained and published from 1957 to 2020. In total, the dataset includes 5141 records of 111 zooplankton species (including 17 subspecies), belonging to 45 genera. These are mainly native species - 98.5%, while the naturalised, including invasive species, accounts for less than 1.5%.A total of 5141 records have been published on the taxonomic diversity and occurrence of zooplankton (rotifers and crustaceans) in the Middle Volga River Basin. Each record includes information about the place and date of finding the specimen, its taxonomy, occurrence and abundance and the collector. If the information about the find has been published, a link to the corresponding reference is provided. The presented dataset supplements the data on the distribution of zooplankton species in the European part of Russia. Data on zooplankton in the Middle Volga River Basin are published for the first time.
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- 2021
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22. Cellulose-Based Metallogels—Part 2: Physico-Chemical Properties and Biological Stability
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Aleksandra Mikhailidi, Irina Volf, Dan Belosinschi, Bogdan-Marian Tofanica, and Elena Ungureanu
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metallogels ,hydrogels ,cellulose ,physico-chemical properties ,biological stability ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
Metallogels represent a class of composite materials in which a metal can be a part of the gel network as a coordinated ion, act as a cross-linker, or be incorporated as metal nanoparticles in the gel matrix. Cellulose is a natural polymer that has a set of beneficial ecological, economic, and other properties that make it sustainable: wide availability, renewability of raw materials, low-cost, biocompatibility, and biodegradability. That is why metallogels based on cellulose hydrogels and additionally enriched with new properties delivered by metals offer exciting opportunities for advanced biomaterials. Cellulosic metallogels can be either transparent or opaque, which is determined by the nature of the raw materials for the hydrogel and the metal content in the metallogel. They also exhibit a variety of colors depending on the type of metal or its compounds. Due to the introduction of metals, the mechanical strength, thermal stability, and swelling ability of cellulosic materials are improved; however, in certain conditions, metal nanoparticles can deteriorate these characteristics. The embedding of metal into the hydrogel generally does not alter the supramolecular structure of the cellulose matrix, but the crystallinity index changes after decoration with metal particles. Metallogels containing silver (0), gold (0), and Zn(II) reveal antimicrobial and antiviral properties; in some cases, promotion of cell activity and proliferation are reported. The pore system of cellulose-based metallogels allows for a prolonged biocidal effect. Thus, the incorporation of metals into cellulose-based gels introduces unique properties and functionalities of this material.
- Published
- 2023
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23. Investigation Of Heavy Metals Content in Raw Milk Samples from Dairy Cows – A Systematic Review
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Adina-Mirela Ariton, Andra-Sabina Neculai-Văleanu, Ioana-Cristina Crivei, Alina-Narcisa Postolache, Cătălina Sănduleanu, Ioana Poroșnicu, and Elena Ungureanu
- Subjects
decontamination ,heavy metals ,milk ,prevention ,rapid methods ,Agriculture ,Technology ,Science - Abstract
Heavy metals toxicity, as well as the cumulative effects on the human body, require regular monitoring of their concentration in cow's milk. In dairy cows, heavy metals can cause loss of appetite, reproductive imbalances, and long-term consequences on milk production, among other concerns. Cow feed quality is directly related to environmental quality and agricultural aspects such as plant type, soil quality, fertilization processes, harvesting, processing, and storage. This literature review highlights various sources of heavy metals in raw milk, methods of decontamination and prevention, as well as classical and innovative techniques for determining the presence of heavy metals in milk. Due to the high concentrations of heavy metals in milk samples, particularly lead and cadmium, health and environmental protection organizations should conduct rigorous assessment. The relevant regulatory agencies should establish and implement more precisely the permitted levels of cadmium, nickel, cobalt, and copper in milk, and each unit that processes milk should be required to adhere to practices and a food safety management program.
- Published
- 2023
24. Incidence of Lead, Cadmium, Chromium, Nickel and Cobalt in Basil, Rosemary and Peppermint Seasonings from Romanian Market
- Author
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Denisa CIOTEA, Elena UNGUREANU, Gabriel MUSTATEA, and Mona Elena POPA
- Subjects
contamination ,food ,heavy metal ,seasonings ,spices. ,Food processing and manufacture ,TP368-456 - Abstract
The use of seasonings is important in food industry because the bioactive compounds contained in these dried aromatic plants improve the taste and the flavor of food. These dried aromatic plants can often be contaminated with some heavy metals, polycyclic carbohydrates residues and pesticides which may occur during the cultivation operation, drying process, manufacture and conditioning. The aim of this study is to determine the contamination with heavy metals (lead, cadmium, chromium, nickel and cobalt) of basil (B), rosemary (R) and peppermint (M) seasonings used in Romanian cuisine. The concentration of lead ranged 0.058 - 0.643 mg.kg-1 (M), 0.209 - 0.493 mg.kg-1 (R), 0.077 - 0.139 mg.kg-1 (B). The concentration of cadmium varied: 0.004 - 0.035 mg.kg-1 (M), 0.004 - 0.007 mg.kg-1 (R), 0.002 - 0.009 mg.kg-1 (B). The concentration of chromium ranged 0.304 - 0.403 mg.kg-1 (M), 0.450 - 0.457 mg.kg-1 (R), 0.208 - 0.336 mg.kg-1 (B). The concentration of nickel varied from 0.376 - 0.848 mg.kg-1 (M), 0.354 - 0.427 mg.kg-1 (R), 0.230 - 0.334 mg.kg-1 (B). The concentration of cobalt ranged 0.037 - 0.167 mg.kg-1 (M), 0.065 - 0.137 mg.kg-1 (R), 0.112 - 0.156 mg.kg-1 (B).
- Published
- 2021
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25. A DISCOURSE ANALYSIS OF CLASS INTERACTIONS
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Elena UNGUREANU
- Subjects
classroom discourse analysis ,curriculum ,interactions ,school knowledge ,students participation ,Education ,Theory and practice of education ,LB5-3640 - Abstract
In this article I analyse the discursive context of two classes of students bringing into discussion the concepts of educational knowledge and the organization of teaching-learning activities. Although there is much research that provides nuanced insights into how teachers and students are involved in the social construction of classroom discourses about knowledge, in Romanian literature the issue of classroom interactions has been approached from the perspective of teachers ‘ and students’ perceptions, while school knowledge has been studied only incidentally Therefore, I present a qualitative study, based on a critical discourse analysis that highlights how different versions of knowledge are socially constructed in the discursive space of the classroom, in order to point out ways in which the classroom and school can become spaces in which interactions no longer revolve around knowledge defined only by reference to disciplinary content. Bimonthly observations and audio-video recordings were made in the 2017-2018 school year during language and communication activities, in two classes, from two different schools. The results show that classroom interactions and participation structures differ depending on the purpose of the activities, and student participation is not only based on generally accepted communication rules, but varies depending on the implicit or explicit purpose of the activities.
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- 2020
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26. Quality Assessment of Bovine Colostrum and Possible Applications in the Dairy Industry
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Adina-Mirela Ariton, Andra-Sabina Neculai-Văleanu, Ioana Poroșnicu, Elena Ungureanu, and Lucia Carmen Trincă
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bovine colostrum ,dairy industry ,physico-chemical properties ,rapid methods ,Agriculture ,Technology ,Science - Abstract
Colostrum is a mammary gland fluid that is produced and secreted throughout the last trimester of pregnancy and the first few days following calving. Colostrum aids in the growth, development, and protection of the new-born calves' immune system. In order for the immunoglobulins to be effective, colostrum it must be given to the new-born within the first few hours of life. Lab tests for IgG levels may be quite precise, but they are time-consuming and not always accessible to farmers. Colostrometer and refractometers could be foreseen as promising tools in the estimation of IgG for distinguishing colostrum of high quality. This paper describes quick methods for evaluating colostrum quality and prospective uses of colostrum in the dairy industry.
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- 2023
27. Cellulose-Based Metallogels—Part 1: Raw Materials and Preparation
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Aleksandra Mikhailidi, Irina Volf, Dan Belosinschi, Bogdan-Marian Tofanica, and Elena Ungureanu
- Subjects
cellulose ,metallogels ,hydrogels ,cellulose-based gels ,dissolution ,Science ,Chemistry ,QD1-999 ,Inorganic chemistry ,QD146-197 ,General. Including alchemy ,QD1-65 - Abstract
Metallogels are a class of materials produced by the complexation of polymer gels with metal ions that can form coordination bonds with the functional groups of the gel. Hydrogels with metal phases attract special attention due to the numerous possibilities for functionalization. Cellulose is preferable for the production of hydrogels from economic, ecological, physical, chemical, and biological points of view since it is inexpensive, renewable, versatile, non-toxic, reveals high mechanical and thermal stability, has a porous structure, an imposing number of reactive OH groups, and good biocompatibility. Due to the poor solubility of natural cellulose, the hydrogels are commonly produced from cellulose derivatives that require multiple chemical manipulations. However, there is a number of techniques of hydrogel preparation via dissolution and regeneration of non-derivatized cellulose of various origins. Thus, hydrogels can be produced from plant-derived cellulose, lignocellulose and cellulose wastes, including agricultural, food and paper wastes. The advantages and limitations of using solvents are discussed in this review with regard to the possibility of industrial scaling up. Metallogels are often formed on the basis of ready-made hydrogels, which is why the choice of an adequate solvent is important for obtaining desirable results. The methods of the preparation of cellulose metallogels with d-transition metals in the present state of the art are reviewed.
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- 2023
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28. AN ANALYSIS OF EDUCATIONAL POLICY MEASURES FOR RURAL EDUCATION
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Elena UNGUREANU
- Subjects
educational policy ,policy paradigm ,policy instruments ,rural education ,social learning ,Education ,Theory and practice of education ,LB5-3640 - Abstract
This study explores the typology of rural education policy measures proposed in the Education Strategies developed between 2002 and 2017. We analyzed twelve strategies, according to an analysis framework that includes the objectives and the instruments proposed for use in relation to problems identified in rural areas. Subsequently, the identified objectives were organized thematically so as to highlight a map of intervention areas in the rural area. Instruments were classified using the Vedung (1998) typology: regulatory, economic and information tools. The intervention areas identified under the objectives were: school responsibility and partnership/lifelong learning, improved school infrastructure, quality of educational provision and equal opportunities for access and participation. Each field corresponds to certain types of instruments, the use of which varies according to the directions of action as well as the period. For example, in the area of school responsibility and partnership or infrastructure, regulatory or economic instruments are used in particular. The patterns identified in the policy tool proposals as well as highlighting rural intervention areas in the education strategies analyzed are a new way to conceptualize the evolution of rural public education policies. An in-depth understanding of strategic planning and proposals for the use of certain policy instruments in rural areas could contribute to the development and delivery more appropriate policies, for the targeted population.
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- 2018
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29. Effects of Cold Rolling Deformation and Solution Treatment on Microstructural, Mechanical, and Corrosion Properties of a Biocompatible Ti-Nb-Ta-Zr Alloy
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Mariana Lucia Angelescu, Alexandru Dan, Elena Ungureanu, Nicoleta Zarnescu-Ivan, and Bogdan Mihai Galbinasu
- Subjects
Ti-Nb-Ta-Zr alloy ,thermo-mechanical treatment ,cold rolling ,solution treatment ,mechanical properties ,corrosion resistance ,Mining engineering. Metallurgy ,TN1-997 - Abstract
One of the most important requirements for a metallic biomaterial is the mechanical biocompatibility, which means excellent mechanical properties—high strength and fatigue strength, but low elastic modulus, to be mechanically harmonized with hard tissues. In order to improve the mechanical and biocompatible performance of the Ti-25.5Nb-4.5Ta-8.0Zr wt% alloy, the influence of cold plastic deformation and solution treatment on its properties were investigated. The Ti-25.5Nb-4.5Ta-8.0Zr wt% alloy was fabricated by melting in a cold crucible furnace (in levitation) and then subjected to several treatment schemes, which include cold rolling and different solution treatments. Microstructural and mechanical characteristics of specimens in as-cast and thermo-mechanically processed condition were determined by SEM microscopy and tensile testing, for different structural states: initial as-cast/as-received, cold rolled and solution treated at different temperatures (800, 900, and 1000 °C) and durations (5, 10, 15, and 20 min), with water quenching. It was concluded that both cold rolling and solution treatment have important positive effects on structural and mechanical properties of the biomaterial, increasing mechanical strength and decreasing the elastic modulus. Samples in different structural states were also corrosion tested and the results provided important information on determining the optimal processing scheme to obtain a high-performance biomaterial. The final processing route chosen consists of a cold rolling deformation with a total deformation degree of 60%, followed by a solution heat treatment at 900 °C with maintenance duration of 5 min and water quenching. By applying this thermo-mechanical processing scheme, the Ti-25.5Nb-4.5Ta-8.0Zr wt% alloy showed an elastic modulus of 56 GPa (5% higher than in the as-cast state), an ultimate tensile strength of 1004 MPa (41.8% higher than in the as-cast state), a yield strength of 718 MPa (40.6% higher than in the as-cast state), and increased corrosion resistance (the corrosion rate decreased by 50% compared to the as-cast state).
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- 2022
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30. CUPRAC Voltammetric Determination of Antioxidant Capacity in Tea Samples by Using Screen-Printed Microelectrodes
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Alina Elena Trofin, Lucia Carmen Trincă, Elena Ungureanu, and Adina Mirela Ariton
- Subjects
Analytical chemistry ,QD71-142 - Abstract
Measurement of antioxidant capacity represents an analytical major challenge in terms of accuracy, efficiency, rapid response, or low cost of detection methods. Quantification of antioxidant capacity of food samples using disposable screen‐printed microelectrodes (SPMEs) was based on cyclic voltammetry versus open-circuit potential (CV vs OCP) and differential pulse voltammetry (DPV) as compared with spectrophotometric measurement of the CUPRAC reaction with 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox). The SPMEs are organic‐resistant electrodes and thus compatible with food samples and organic solvents used to dissolve trolox. A micropipette was used to release a drop of 50 μL sample on the spotted surface of the SPME sensor/working electrode that was time programmed to function according to the working protocol. The SPME response was linearly correlated with trolox content. This preliminary demonstration was focused on the analysis of tea infusions, due to the simplicity and reproducibility of the samples’ preparations involved. Analytical results of the antioxidant capacity (expressed as mol·L−1 trolox equivalents) of the tea samples showed a good agreement in the case of spectrophotometry and differential pulse voltammetry (R2 > 0.998). DPV with SPME based on CUPRAC reactions was proven to be a promising approach for the characterization of antioxidant capacity of tea samples with rapid response, cost-effectiveness, and simplicity of operation.
- Published
- 2019
- Full Text
- View/download PDF
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